TOHATSU BFT250A Service Manual page 159

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3. Knock sensor inspection
Replace the knock sensor with a new one and
perform the knock sensor symptom reproduction
test.
Does the DTC 23-1 appear?
YES
NO
DTC 41-2 (ABNORMAL HO2S HEATER)
ECM
O2HT
1. Symptom reproduction test
Turn the combination switch OFF.
Disconnect the HO2S 4P connector
connector A
Clear the DTC (page 5-6).
• Continue the procedure if the DTC does not
Start the engine and let it run at 3,000 min
5 minutes or more under no load.
Let the engine idle for a minute or more.
Check the DTC using the HDS.
Does the DTC 41-2 appear?
YES
NO
– Replace the ECM with a new one and
recheck.
– Faulty original knock sensor. End of
inspection.
W/Bl
, junction box 23P connector
and then reconnect them.
clear.
– GO TO STEP 2.
– Temporary failure
reappear).
W/Bl
Y/Bl
Y/Bl
FUSE/RELAY JUNCTION BOX
10
No.10
FUSE
(10 A)
, ECM
-1
(rpm) for
(code does not
FUEL SYSTEM
HO2S
HEATER
W
W
Bl: Black Br: Brown
Y: Yellow O: Orange
Bu: Blue Lb: Light blue
G: Green Lg: Light green
R: Red P: Pink
W: White Gr: Gray
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